Strengthen and prevention of deformation
Plastic product design
Strengthen and prevention of deformation
Soluction
1. Add R on corner
The sharp corners of plastic product are often the biggest factor in casuing product demage. To eliminate sharp corners is not just reduce the stress concentration area and increase structural strength, and can also be made of plastic material molding with flow line and is easier for tooling release. In addition, the views from the mould, radius corner is also beneficial to mold making and mould strength.
All product inside and outside corner radius should be larger as possible to eliminate stress concentration, but too large radius will cause shrinkage. especially in the ribs or the roots of boss. In principle, the smalles angle should be 0.020 to 0.030 ich.
As above, radius corner for plastic product design will have following advantages:
1. Radius corner molding products made to improve strength and reduce innerstress
2. The eliminiation of sharp corners, automatically reduces the possibility of cracking, on the other words it increase the sudden shock or impact resistance.
3. The plastic flwo of the situation will be significant imprrovement; Allowing the plastic to uniform, there is no residual flow phenomena; Less innerstress on the product cross-section area; Improving the density of the molded coress-section area.
4. Mould strength is improved. To prevent the sharp corner in the mould resluting in stress concentration leading to cracking, especially for the need of heat treatment radius corner are much more important.
The bigger corner, the more innerstress
Inside corner R<0.3T----innerstress dramatic increasing
Inside corner R>0.8T----almost no stress concentration.
PC,PPO T<0.6T PA,PE T<0.5T PMMA,ABS T<0.5T PS T<0.6T
